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Search Results: 1 - 10 of 3913 matches for " Satoshi Hayashi "
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Bi-Directional Excitation of Radio Frequency Waves Using a Helical Antenna in Non-Uniform Plasmas towards a Compact Magnetoplasma Thruster  [PDF]
Yasuyoshi Yasaka, Yoshifumi Hayashi, Hiromasa Takeno, Satoshi Nakamoto
Open Journal of Applied Sciences (OJAppS) , 2014, DOI: 10.4236/ojapps.2014.413051
Abstract: Magnetoplasma thruster is one of the attractive plasma engines for space propulsion in future manned deep space exploration. Usually two helical antennas are equipped to produce and heat plasmas with separate radio frequency sources. It is presented in this paper that a helical antenna, which is used to launch one wave mode in one direction so far, exhibits bi-directional nature, where the waves with different mode numbers are launched and couple with electrons and ions selectively in opposite directions. A two-dimensional numerical calculation is performed to predict wave propagation and power absorption in a non-uniform hydrogen plasma immersed in a non-uniform external static magnetic field, based on the hot plasma theory. It is confirmed that appropriate choice of the excitation condition of the antenna can select axial propagation direction of specific wave modes and consequently select a species that absorbs power from generated waves. A small-scale experiment is performed to confirm the prediction of the calculation. By measuring a change in electron and ion temperatures due to the wave launch from the helical antenna, it is found that both the production and heating at different axial positions are accomplished simultaneously by one antenna showing that another type of the radio frequency driven magnetoplasma thruster would be achieved.
Intramedullary Spinal Cord Metastases in Breast Cancer: Report a Case  [PDF]
Masahiro Kitada, Nana Takahashi, Shunsuke Yasuda, Satoshi Okazaki, Kei Ishibashi, Satoshi Hayashi
Journal of Cancer Therapy (JCT) , 2016, DOI: 10.4236/jct.2016.713099
Abstract: Background: Intramedullary spinal cord metastasis (ISCM) from breast cancer is a relatively rare disease. We present this disease. Case presentation: The patient was a 67-year-old woman with lung metastasis appearing 3 years after breast cancer surgery. Complete remission was achieved for the metastatic lesion with chemotherapy, but multiple cerebellar metastases were found 3 months after the completion of chemotherapy. Whole-brain irradiation was administered, resulting in symptomatic improvement. Approximately 6 months later, the patient experienced weakness in the lower extremities and difficulty walking. Magnetic resonance imaging detected a well-defined intraspinal tumor measuring 13 × 13 × 30 mm at the level of Th12-L1. After 20-Gy irradiation to the tumor, oral steroid administration, and rehabilitation, the patient regained the ability to walk. Eight months have passed, to date, since these interventions and the patient is currently receiving treatment for metastases to bones, including the spine, but is still capable of walking without difficulty. We herein report this case with a review of the relevant literature. Conclusion: ISCM in the breast cancer is relatively rare. But, it is the clinical condition which it should always place in the mind.
Clinicopathological Study of Epithelial Metaplastic Breast Cancer  [PDF]
Masahiro Kitada, Shunsuke Yasuda, Nana Takahashi, Satoshi Okazaki, Kei Ishibashi, Satoshi Hayashi
Journal of Cancer Therapy (JCT) , 2016, DOI: 10.4236/jct.2016.713100
Abstract: Introduction: Metaplastic breast cancer (MBC) is a rare pathological type with an incidence rate of not more than 1%, and has been reported to be often detected after its progression and highly malignant with a high proportion of triple negative type tumors, with poor outcomes as compared to IDC [1] [2] [3]. We analyzed clinicopathological characteristics of patients who underwent surgery for epithelial MBC at our department. Patients and Methods: From January 2000 to March 2014, a total of 2120 patients underwent surgery for breast cancer, and MBC was diagnosed in 15 of these patients. Fourteen of the 15 had epithelial MBC and were included in this study. The present study compared clinopathological characteristics of MBC with those of IDC of triple negative type (TN type group) and IDC of non-triple negative type (IDC group). Results: Breast conserving surgery was performed in 7 patients with MBC (50%), a proportion clearly lower than the 64.3% in the IDC group. The mean tumor size was 3.8 cm, which was greater than the 2.13 cm in the TN type group and the 1.7 cm in the IDC group. About nuclear grade, the proportion of grade III was 57.1%, markedly higher than the 38.6% in the TN type group and the 12.6% in the IDC group. All patients were estrogen receptor (ER) and progesterone receptor (PgR) negative; 11 patients were TN type tumors and 3 were HER2 type. Conclusion: We studied patients who underwent surgery for epithelial MBC. The examined cases showed clinopathological characteristics of the disease, including large tumors with a highly malignant nature at the initial detection, higher Ki-67 levels, ER and PgR negativity (all cases), mostly TN type, and a high recurrence rate.
Surgical Treatment of Idiopathic Multiple Pulmonary Arteriovenous Malformation Identified at the Onset of Cerebral Infarction: A Case Report  [PDF]
Masahiro Kitada, Shunsuke Yasuda, Nana Takahashi, Satoshi Okazaki, Kei Ishibashi, Satoshi Hayashi, Yoshinobu Ohsaki
Open Journal of Respiratory Diseases (OJRD) , 2017, DOI: 10.4236/ojrd.2017.72007
Abstract: Pulmonary arteriovenous malformation (PAVM), which is asymptomatic in most cases, is often identified in patients with central nervous system disorders such as brain abscesses and/or cerebral infarctions. We have reported a patient with idiopathic multiple PAVM identified at the onset of cerebral infarction. A 69-year-old woman visited the Department of Neuropathic Internal Medicine at our hospital with chief complaints of numbness in her left hand and a feeling of weakness. The patient was given a diagnosis of subacute cerebral infarction. Multiple old lacunar infarctions were also observed in the deep white matter of the left frontal lobe. Chest computed tomography showed multiple nodular structures, mainly in the right lower lung field (S8), as well as continuous arteries and veins at the site; thus, the patient was finally diagnosed with multiple PAVM. Right lower thoracoscopic lobectomy was performed, as is typical surgical practice in such cases. The patient had a favorable postoperative course, and had no recurrence of cerebral infarction. Although the patient’s lesions were mainly restricted to S8, the fact that there were multiple lesions deemed a lobectomy as the appropriate course of treatment. This case emphasizes that attention should be paid to cases of multiple PAVM since cerebral infarction may arise from the disease.
Clinicopathological Study of Neuroendocrine Carcinoma of the Breast  [PDF]
Masahiro Kitada, Shunsuke Yasuda, Masahiro Abe, Nana Takahashi, Satoshi Okazaki, Kei Ishibashi, Satoshi Hayashi
Journal of Cancer Therapy (JCT) , 2017, DOI: 10.4236/jct.2017.88069
Abstract: Introduction: Neuroendocrine carcinoma (NEC) occurs mostly in the digestive organs, such as the pancreas and gastrointestinal tract, and the lungs. Primary NEC of the breast is a rare entity. There are not many studies on this disease, and this study was carried out in order to know the clinical pathology of this disease. Methods: Of 2354 patients who underwent surgery for breast cancer in our hospital during the period from January 2000 to July 2015, 8 (0.34%) were pathologically diagnosed with NEC of the breast. This study is retrospectively registered. Result: The histological types were small cell carcinoma in one patient and invasive ductal carcinoma (IDC) with neuroendocrine differentiation in the remaining 7. The mean patient age was slightly higher than that of patients with usual IDC. On pathological examination, the NEC tumors were more hormone dependent and often HER2 negative, as compared to usual IDC, though there was no significant difference in nuclear grade. The patients with NEC of the breast showed positivity for neuroendocrine markers on immunohistological staining, and had favorable outcomes. Conclusion: NEC of the breast is rare, and there is no established consensus regarding the pathological significance, prognosis, and treatment method. Further accumulation of cases is necessary.
A Multicenter Cohort Study for XELOX (Capecitabine, Leucovorin plus Oxaliplatin) Therapy as First-Line Treatment in Elderly Patients with Unresectable Colorectal Cancer  [PDF]
Tetsu Yamamoto, Ryoji Hyakudomi, Shinichi Sugimoto, Atsuo Tokuka, Yoshitoshi Sato, Satoshi Nagai, Hikota Hayashi, Masahikoo Igarashi, Kenji Takubo, Yoshitsugu Tajima
Journal of Cancer Therapy (JCT) , 2015, DOI: 10.4236/jct.2015.62017
Abstract:

Oxaliplatin-based chemotherapy with bevacizumab is now widely used for colorectal cancer patients. This study evaluated the efficacy and tolerability of XELOX (capecitabine + oxaliplatin + leucovorin combined) therapy with or without bevacizumab in elderly patients. One hundred and seven patients, consisting of 52 elderly (>70 years of age) and 55 non-elderly, with unresectable colorectal cancer were enrolled in this multicenter cooperative group study using a database between October 2009 and March 2012. We evaluated the outcomes in terms of the median time to treat failure (TTF), overall response rate (ORR), disease control rate (DCR) and tolerability in both age groups. The median TTF for the XELOX + bevacizumab regimen was 7.1 months in the non-elderly group and 8.1 months in the elderly group (p = 0.838). There was no significant difference in TTF between the two groups. The ORR and DCR in the non-elderly group were 30.8% and 73.1%, respectively. In the elderly group, the ORR was 40.0% and the overall DCR was 90.0%. No severe or uncontrollable adverse events were observed in the two groups. These data indicated that the XELOX chemotherapy with or without bevacizumab has an equivalent efficacy in both groups, without increasing the adverse events even in the elderly population.

Weight and volume reduction of organic sludges and enhanced recovery of biomass resources using sonophotocatalysis
Naohito Hayashi,Satoshi Koike,Ryosuke Yasutomi,Eiki Kasai
Songklanakarin Journal of Science and Technology , 2010,
Abstract: The efficiency of sonophotocatalysis, a pretreatment process involving ultrasonic irradiation and photocatalysis, in decreasing the emission amount of sewage sludge and enhancing the recovery of valuable materials, was investigated experimentally. The results indicated a 50% reduction in the sewage sludge emission after sonophotocatalysis was carried out for 2 h. In addition, the recovery ratio of methane gas by anaerobic digestion and dissolved phosphorus were 1.7 and 2.5 times more than those of methane and phosphorus in the recovery process without pretreatment, respectively.
Modified wave operators for nonlinear Schrodinger equations in one and two dimensions
Nakao Hayashi,Pavel I. Naumkin,Akihiro Shimomura,Satoshi Tonegawa
Electronic Journal of Differential Equations , 2004,
Abstract: We study the asymptotic behavior of solutions, in particular the scattering theory, for the nonlinear Schr"{o}dinger equations with cubic and quadratic nonlinearities in one or two space dimensions. The nonlinearities are summation of gauge invariant term and non-gauge invariant terms. The scattering problem of these equations belongs to the long range case. We prove the existence of the modified wave operators to those equations for small final data. Our result is an improvement of the previous work [13]
Palladium-Catalyzed Polyfluorophenylation of Porphyrins with Bis(polyfluorophenyl)zinc Reagents
Noriaki Sugita,Satoshi Hayashi,Sawa Ishii,Toshikatsu Takanami
Catalysts , 2013, DOI: 10.3390/catal3040839
Abstract: A facile and efficient method for the synthesis of pentafluorophenyl- and related polyfluorophenyl-substituted porphyrins has been achieved via palladium-catalyzed cross-coupling reactions of brominated porphyrins with bis(polyfluorophenyl)zinc reagents. The reaction is applicable to a variety of free-base bromoporphyrins, their metal complexes, and a number of bis(polyfluorophenyl)zinc reagents.
The Disappearing Envelope around the Transitional Class I Object L43
Shin Koyamatsu,Shigehisa Takakuwa,Masahiko Hayashi,Satoshi Mayama,Nagayoshi Ohashi
Physics , 2014, DOI: 10.1088/0004-637X/789/2/95
Abstract: We present SMA interferometric observations of the 12CO J=2-1, 13CO (J=2-1), and C18O (J=2-1) lines and 225 GHz continuum emission and SMT single-dish observations of C18O (J=2-1) toward L43, a protostellar object in transition from Class I to II. The 225 GHz continuum emission shows a weak (~23.6 mJy), compact (<1000 AU) component associated with the central protostar. Our simulated observations show that it can be explained by dust thermal emission arising from an envelope which has a hole or a constant intensity region within a few hundred AU of the protostar. This suggests the disappearance or a lower concentration distribution of the envelope on a small scale. The 12CO and 13CO emission exhibit molecular outflows to the south and north. The C18O emission shows two molecular blobs, which correspond to the reflection nebulosity seen in near-infrared images, while there is no C18O emission associated with the protostar. The near-infrared features are likely due to the scattering at the positions of the blobs. The visible scattering features should result from the optical thinness of the envelope material, which is consistent with the less-concentrated distribution in the continuum emission. From single-dish observations, we found that the mass of the envelope (~1.5 Msun) + protostar (~0.5 Msun) is comparable with the virial mass of M_vir=1.0 Msun within 40 arcsec. This suggests that the envelope is likely gravitationally bound. We suggest that the protostellar envelope of L43 has been disappearing by consumption through accretion, at least in the close vicinity of the protostar.
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